1. Field of the Invention
The present invention relates to the field of monoclonal antibodies and their use in the treatment of diseases and disorders. More specifically, the invention relates to monoclonal antibodies that specifically bind to the cytokine IL-6, and to uses of the antibodies for the treatment of diseases and disorders associated with IL-6 activity or expression.
2. Related Art
Interleukin-6 (IL-6) is a 22 to 27 kDa secreted glycoprotein which exhibits growth stimulatory and proinflammatory activities. IL-6 is also known as interferon-β2 (IFN-β2), IL-1 inducible 26-kDa protein, hepatocyte-stimulating factor, cytotoxic T-cell differentiation factor, and B-cell stimulatory factor. (Trikha et al., Clin. Cancer Res. 9:4653-4665 (2003)). IL-6 is secreted by various cell types. IL-6 exerts its activities through binding to a high-affinity receptor complex consisting of two membrane glycoproteins: an 80 kDa component receptor that binds IL-6 with low affinity (IL-6R) and a signal-transducing component of 130 kDa (gp130) that does not bind IL-6 by itself, but is required for high-affinity binding of IL-6 by the complex. (See FIG. 11; BioCarta). IL-6R can be cleaved by a transmembrane metalloproteinase to yield the soluble IL-6R.
IL-6 blood levels are elevated in numerous infectious, inflammatory, and autoimmune diseases and in cancer in association with increased synthesis of other cytokines stimulated by infection, trauma, and immunological challenge. (Trikha et al., Clin. Cancer Res. 9:4653-4665 (2003)).
IL-6 has been implicated in various diseases and disorders such as multiple myeloma (Rossi et al., Bone Marrow Transplantation 36:771-779 (2005)), lymphomas (Emilie et al., Blood 84:2472-2479 (1994)), neurological disorders such as neurodegeneration, astrocytosis and cerebral angiogenesis (Campbell et al., Proc. Natl. Acad. Sci. 90:10061-10065 (1993)), autoimmune disorders (such as, e.g., rheumatoid arthritis), inflammatory diseases, Alzheimer's disease, myocardial infarction, Paget's disease, osteoporosis, solid tumors, prostatic and bladder cancers (Trikha et al., Clin. Cancer Res. 9:4653-4665 (2003)), septic shock, transplant, acute infections of the central nervous system, cardiac myxoma (Wijdenes et al., Mol. Immunol. 28:1183-1192 (1991)), tumor-induced cachexia (Cahlin et al., Cancer Res. 60:5488-5489 (2000)), cancer-associated depression, and cerebral edema secondary to brain tumors (Musselman et al., Am. J. Psychiatry 158:1252-1257 (2001)).
In addition, anti-IL-6 antibodies have been shown to be effective in treating several diseases and disorders. For example, anti-IL-6 monoclonal antibodies have been shown to block the proliferation of myeloma cells both in vivo and in vitro. (Rossi et al., Bone Marrow Transplantation 36:771-779 (2005)). Administration of anti-IL-6 antibodies to chronic rheumatoid arthritis patients was found to alleviate the symptoms of the disease (Wendling et al., J. Rheumatol. 20:259-262 (1993)). Anti-IL-6 antibodies have also been shown to be effective in treating AIDS-associated lymphoma (Emilie et al., Blood 84:2472-2479 (1994)), and metastatic renal cell carcinoma (Blay et al., Int. J. Cancer 72:424-430 (1997). Clinical results involving the administration of anti-IL-6 antibodies to treat various other diseases and disorders are summarized in Trikha et al., Clin. Cancer Res. 9:4653-4665 (2003).
Anti-IL-6 antibodies are known in the art. For example, reshaped human (i.e., humanized) anti-IL6 monoclonal antibodies derived from a mouse monoclonal antibody (SK2) are set forth in U.S. Pat. Nos. 5,618,700 and 5,856,135. Other anti-IL-6 antibodies include an antibody known as CLB-6/8 (Brakenhoff et al., J. Immunol. 145:561-568 (1990)) and a chimeric form thereof, known as cCLB8 (Van Zaanen et al., J. Clin. Invest. 98:1441-1448 (1996). A murine anti-IL-6 monoclonal antibody (mAb) designated B-E8 has been clinically used to treat various IL-6-associated diseases and disorders. (See, e.g., Bataille et al., Blood 86:685-691 (1995), Rossi et al., Bone Marrow Transplantation 36:771-779 (2005), Haddad et al., Blood 15:1590-1597 (2001), and Emilie et al., Blood 84:2472-2479 (1994)).
The use of murine antibodies, including murine anti-IL-6 antibodies, is compromised by problems such as variable selectivity for the target antigen, short serum half-lives, and the development of human anti-murine antibodies (HAMA). These issues are reduced to some extent by the development of chimeric antibodies (in which rodent constant regions are replaced by their human counterparts) or humanized/CDR-grafted/reshaped antibodies (in which only the CDRs are of non-human origin). (See generally, Vaughan et al., Nat. Biotech. 16:535-539 (1998)). Nonetheless, a number of practical limitations are associated with humanized antibodies, such as (1) the limited number of options for routes for efficient construction of humanized mAbs, (2) the need for detailed knowledge of antibody structure or modeling, (3) unpredictable immunogenicity due to a compromise between affinity retention and introduced foreign amino acids, and (4) limitations in the antibody repertoire to the animal in which the progenitor mAb originated. (Vaughan et al., Nat. Biotechnol. 16:535-539 (1998)). These limitations may be addressed by the use of human monoclonal antibodies. (Lonberg, Nat. Biotechnol. 23:1117-1125 (2005)).
There is therefore a need in the art for additional anti-IL-6 monoclonal antibodies for clinical applications, including human anti-IL-6 mAbs. The present invention addresses this existing need in the art.